Solid state bell ringing system

ABSTRACT

A solid state bell ringing system having no mechanically moving parts and including a bell, a power source, a ringing circuit having an electromagnet and a triggering circuit. The electromagnet is positioned adjacent the bell and coupled to the power source. The triggering circuit is electrically coupled to the ringing circuit and the power source. The triggering circuit controls the ringing circuit to provide repeated energization of the electromagnet which thereby results in elastic deformation of the bell and therefore an audible ringing.

United States Patent 1191 1111 3,868,683 Darrow 1 Feb. 25 1975 SOLID STATE BELL RINGING SYSTEM v 3,532,131; 1 4 /1970 kezary 317/151 1 1 1mm John 9 DamMurrysviHe 312011113 8/1371 visfiffffiiiiiiijj 3311111 [73] Assignee: Westinghouse Air Brake Company,

Swissvale, Pa, Primary Examiner-Donald J. Yusko Assistant Examiner-William M. Wannisky [22] Filed: 1971 Attorney, Agent, or Firm-A. G. Williamson, Jr.; R. [21] Appl. No.: 170,927 W. Mclntire, Jr.

[52] us. or 340/384 R, 340/402, 331/64, [57] A BSTRACT 331/111, 331/157, 317/143? 307/252 R, solid stete bell rmgmg system havmg no mechani- 31O/26 caliy moving parts and including a bell, a power [51] Int. Cl. G08b 3/00 source a ringing circuit having an electromagnet and 5 w of Search 340/392 397, 8 R, 401 a triggering circuit. The electromagnet is positioned 340/402; 331/64, 110-112, 157; 317/143; djacent the bell and coupled to the power source. 318/118; 0/26; 84/101; 307/252 R "ljhe trlggern g circuit is electrically coupled to the ringing circuit and the power source. The triggering 5 Reierences Cited circuit controls the ringing circuit to provide repeated energization of the electromagnet which thereby re- UNITED STATES PATENTS suits in elastic deformation of the bell and therefore 2,723,386 11/1955 Camp 310/26 UX an audible ringing 2,759,179 8/1956 Kircher 340/401 3,165,591 1/1965 Flowers 331/64 X 6 C ims, 3 Drawing Figures 3,197,716 7/1965 Wright et a1 331/11 Q6636 1 H5 51% l M l/ 20 1 l I1 I i e l 1 L B L' '1' r 23 Z Y 5'68 1] 1H B6 1 1 l $2 I I L 1 1 SOLID STATE BELL RINGING SYSTEM This invention relates to a solid state bell ringing system.

More specifically this invention relates to a solid state bell ringing system which includes an elastically deformable bell which rings during deformation when in the presence of a pulsating magnetic field. The system, in addition, includes a high voltage power source, a ringing circuit having an electromagnet and a triggering circuit. The electromagnet is positioned adjacent the elastically deformable bells periphery and is electrically coupled -to the power source. The triggering circuit is electrically coupled to the ringing circuit, the electromagnet and the power source. The triggering circuit is designed to control the ringing circuit and the energization of the electromagnet to provide repeated periodic energization of the electromagnet which results in the elastically deformable bell deforming in a manner that produces an audible ringing of the bell without the bell coming into contact with any mechanically movable parts.

In railway highway crossing warning applications, alarm circuit arrangements for indicating an approaching vehicle customarily employ a bell having electromechanical hammers which strike the bell surface at a typical rate of twice per second to provide an audible warning indication. Accordingly, various contacts,

shafts, links, etc. are employed in this type of electromechanical arrangement which are subject to wear and require frequent maintenance and, a fortiori, frequent expenditure. Further, a failure in this type of warning arrangement, due to the breaking of the electromechanical hammers, for example, could result in catastrophic damage to persons and equipment. To this type of environment is brought the invention to be described which avoids all these problems and presents thereto a novel and economical solution.

It is therefore an object of this invention to provide a solid state bell ringing system without the need for mechanical devices which are subject to mechanical failure or maintenance.

h is another object of this invention to provide a solid state bell ringing system which relies for the ringing of the hell on the elastic deformation of the bells periphery at a periodic rate under the influence of an electromagnet which is adjacent the bells periphery and is alternately energized and deenergized to induce the deformation of the bell.

Yet another object of this invention is to'provide an improved electronically controlled electromagnetic circuit having a bell alarm indication device which is simple in maintenance and construction, economical in cost, and efficient and reliable in operation.

In the attainment of the foregoing objects, a solid state bell ringingsystem has been invented and includes in combination an elastically deformable bell, a power source, a ringing circuit having an electromagnet and a triggering circuit. The electromagnet is positioned adjacent the bell and is electrically coupled to the power source. The triggering circuit is electrically coupled to the ringing circuit, the electromagnet and the power source. The triggering circuit controls the ringing circuit and the electromagnet to provide repeated periodic energization of the electromagnet which results in the elastically deformable bell deforming in a manner that produces an audible ringing of the bell without the bell coming into contact with the electromagnet.

The ringing circuit includes an energy storage device connected across a serial connection of a control gate and the electromagnet. The power source in turn is connected across the energy storage device of the ringing circuit.

The triggering circuit which is electrically connected to the power source is also controllingly coupled to the control gate of the ringing circuit. A first predetermined amount of energy is stored in the energy storage device of the ringing circuit during the presence of high voltage from the power source. The triggering circuit is designed .to enable the control gate of the ringing circuit and cause the first predetermined amount of energy stored in the energy storage device of the ringing circuit to be discharged through the electromagnet of the ringing circuit and to periodically thereafter pulse the ringing circuit about twice per second. The bell therefore. provides a ringing indication due to its deformation during the discharge of the first predetermined amount of energy through the electromagnet. The electromagnet in turn disables the gate upon total discharge of the first predetermined amount of energy. The energy source is then recharged, and now the entire system is ready to repeat its cycle to produce a ringing of the bell each time the triggering circuit fires.

Other objects and advantages of the present invention will become apparent from the ensuing description of the illustrative embodiment thereof, in the course of which reference is had to the accompanying drawing which illustrates the solid state bell ringing system of the present invention.

Reference is now made to the drawing in which is shown, in substantially schematic form, the electronically controlled electromagnetic circuit arrangement of the present invention. Shown in the drawing is a power source 11 of several hundred volts, connected to a ringing circuit 13 via lead 12 through an inductor L and a diode D and also via common lead 14. As is well known, when a capacitor is charged through a resistor, half of the energy is lost. The inductor L and diode D are employed to recharge capacitor C1 with high efficiency, a method well known to those skilled in the art. The ringing circuit 13 includes a capacitor C1, an electromagnet M and a silicon controlled rectifier SCR having a gate electrode 21, an anode electrode 22, and a cathode electrode 23. An alarm indication device 20, a bell in the preferred embodiment, is positioned adjacent the electromagnet M. The capacitor C1 is connected at one end to the cathode electrode of the diode D and at the other end to lead 14. The electromagnet M is connected at one end to the capacitor C1 and at the other end to the anode electrode 22 of silicon controlled rectifier SCR. The cathode electrode 23 of the silicon controlled rectifier SCR is connected to the common lead 14, while the gate electrode 21 of the silicon controlled rectifier SCR is connected to a triggering circuit 18 through a coupling capacitor C3. A resistor R6 is connected from the junction of the gate electrode 21 of silicon controlled rectifier SCR and coupling capacitor C3 to the common lead 14.

The triggering circuit 18, connected to the power source 11 via lead 16, preferably takes the form of a relaxation oscillator and includes first, second, third, and fourth resistors R1, R2, R3, and R4, respectively, a capacitor C2 and a unijunction transistor Q1 having an emitter electrode 31, a firstbase electrode 32 and a second base electrode 33. The first resistor R1 is connected to the lead 16 at one end, the other end being connected toone end of capacitor C2. The other end of capacitor C2 is connected to the common lead 14.

The second resistor R2 of the triggering circuit 18 is connected from the junction of the first resistor R1 and the capacitor C2 to the emitter electrode 31 of the unijunction transistor Q1. The third resistor R3 of triggering circuit 18 is connected from the second base electrode 33 of unijunction transistor Q1 to the lead 16. The fourth resistor R4 of triggering circuit 18 is connected from thefirst base electrode 32 of unijunction transistor O1 to the common lead 14. The junction of the first base electrode 32 of unijunction transistor Q1 and resistor R4 is connected through coupling capacitor C3 to the gate electrode 21 of silicon controlled rectifier SCR. A resistor R5 is connected from the junction of resistor R3 and the second base electrode 33 of unijunction transistor O1 to common lead 14 to provide a voltage dividing function for limiting the base to base voltage of unijunction transistor Q1.

Turning now to the operation of the circuit arrangement shown in the drawing, it will be appreciated that initially neither the silicon controlled rectifier SCR of the ringing circuit 13 nor the unijunction transistor Q1 of the triggering circuit 18 is conducting. Accordingly, upon the presence of a positive voltage on lead 12 from the power source 11, the capacitor C1 of ringing circuit 13 will be charged to a preselected potential from powersource 11 over lead 12, through inductor L and diode D. At the same time, the voltage appearing on lead 12 will be delivered over lead 16 through resistor R1 of triggering circuit 18 to begin charging capacitor C2 of triggering circuit 18. When a predetermined amount-of charge has been stored in capacitor C2, the potential'at the upper plate of capacitor C2 and at the emitter electrode 31 of unijunction transistor Q1 through resistor R2 will be such that the unijunction transistor 01 begins conducting. Upon conduction of unijunction transistor Q1, a signal will be present at first-base electrode 32 ofunijunction transistor Q1 and delivered via coupling capacitor C3 to the gate'electrode 21 of. silicon controlled rectifier SCR of the ringing circuit 13. Accordingly, silicon controlled rectifier SCR will be enabled, or turned -on7 and begin conducting.

With silicon controlled rectifier SCR conducting, ca-

pacitor C1 of ringing circuit 13 will discharge the preselected amount of charge previously stored therein through electromagnet M, anode electrode 22 of silicon controlled rectifier SCR, cathode electrode 23 of silicon controlled rectifier SCR, to common lead 14, thereby causing electromagnet M to become energized. Upon energization of electromagnet M the periphery of l the bell willbe pulled toward electromagnet M, as

shown in the drawing, in dotted outline characterized by reference numeral 20a. I

Since capacitor C1 and electromagnet M of ringing circuit 13 also constitute a resonant circuit, the oscillation is begun by the turning on of the silicon controlled rectifier SCR and continues until the current through the silicon controlled rectifier SCR tries to re verse, thereby disabling the silicon controlled rectifier SCR to a'state of nonconduction. That is, once capacitor C1 has discharged into electromagnet M due to the conduction of silicon controlled rectifier SCR, the electromagnet M will act as a source to cause reversal of current flow through ringing circuit 13. Under this condition, a positive potential appears at the cathode electrode 23 with respect to the anode electrode 22 of silicon controlled rectifier SCR and the silicon controlled rectifier SCR is reverse biased and accordingly is turned off. This is known as resonant commutation of a silicon controlled rectifier. With silicon controlled rectifier SCR in a state of non conduction, an energization path for electromagnet M will no longer be maintained. Hence, electromagnet M will become deenergized and the periphery 20a of bell 20 will return to its original position, shown in solid outline in the drawing and beyond, going through several oscillations which constitute the ringing sound. By this time, coupling capacitor C3 will have discharged through the resistor R6. Current which had built up in inductor L continues with an oscillation between inductor L and capacitor C1, but when this oscillation reaches the point of current reversal, it is stopped by diode D, and capacitor C1 is recharged to a potential approximately twice that of the magnitude of the incoming voltage level after the first charging of capacitor C1, with minimum power loss. It will be appreciated that the inductance of inductor L should be, made large enough so that negligible current buildup takes place in inductor L during the time that the silicon controlled rectifier is conducting.

' it will further be appreciated that in order to obtain a stood that the invention may have utility in other systems and unrelated areas tions. j V

'It will be appreciated, therefore, that the foregoing description of my inventionis only illustrative and it is not intended that the invention be limited thereto.

Thus, sundry variations, alterations and-modifications may be made by those skilled in the art without depart ing from the spirit and scope of myinvention;

Having thus described my invention, what I claim is:

1. A solid state bell ringing arrangement comprising in combination, 1

a. an elastically deformable bell device responsive when repeatedly deformed by a pulsating magnetic force for producing an audible ringing sound,

b. an electromagnet placed adjacent said bell device for deforming said bell device when the magnet is energized by an energy pulse,

c. a source of direct current energy,

d. an energy storage arrangement comprising a capacitor, an inductor, and a diode connected in series across said energy source for efficiently charging said capacitor when discharged,

' e. a normally non-conducting silicon controlled rectifier having a gating electrode and with its conduction path connected in series with said electromagnet across said capacitor, and r i a f. a relaxation oscillator circuit arrangement having an output terminal coupled to said gating electrode of said controlled rectifier for periodically actuatremote from railway applicaing said rectifier to conduction to discharge said capacitor through said electromagnet.

2. The solid state bell ringing system of claim 1 wherein said relaxation oscillator circuit arrangement comprises a first, a second, a third, and a fourth resistive element, a triggering energy storage means and a semiconductor device, said first resistive element serially connected with said triggering energy storage means across said energy source, said second resistive element connected from the junction of said first resistive element and said triggering energy storage means to said semiconductor device, said third resistive element connected from said semiconductor device to said first resistive element and said energy source, said fourth resistive element connected from said semiconductor device to said triggering energy storage means, said semiconductor device also connected'to said gating electrode of said controlled rectifier, said semiconductor device conducting upon the storage of a predetermined amount of energy by said triggering energy storage means to actuate said controlled rectifier to discharge said capacitor through said electromagnetic means.

3. The solid state bell ringing system of claim 2 wherein a fifth resistive element is connected from the junction of said third resistive element and said semiconductor device to said energy source.

4. The solid state bell ringing system of claim 3 wherein a coupling capacitor is interposed between said semiconductor device and said gate electrode of said controlled rectifier.

5. The solid state bell ringing system of claim 4 wherein a sixth resistive element is connected from the junction of said coupling capacitor and said gate to said power source.

6. The solid state bell ringing system of claim 4 wherein said semiconductor device is a unijunction transistor having an emitter electrode, a first base electrode and a second base electrode, said emitter electrode of said unijunction transistor connected to the junction of said first resistive element and said triggering energy storage means through said second resistive element, said first base electrode of said unijunction transistor connected to said fourth resistive element and through said coupling capacitor to said gating electrode of said controlled rectifier, and said second base electrode of said unijunction transistor connected to said third resistive element. 

1. A solid state bell ringing arrangement comprising in combination, a. an elastically deformable bell device responsive when repeatedly deformed by a pulsating magnetic force for producing an audible ringing sound, b. an electromagnet placed adjacent said bell device for deforming said bell device when the magnet is energized by an energy pulse, c. a source of direct current energy, d. an energy storage arrangement comprising a capacitor, an inductor, and a diode connected in series across said energy source for efficiently charging said capacitor when discharged, e. a normally non-conducting silicon controlled rectifier having a gating electrode and with its conduction path connected in series with said electromagnet across said capacitor, and f. a relaxation oscillator circuit arrangement having an output terminal coupled to said gating electrode of said controlled rectifier for periodically actuating said rectifier to conduction to discharge said capacitor through said electromagnet.
 2. The solid state bell ringing system of claim 1 wherein said relaxation oscillator circuit arrangement comprises a first, a second, a third, and a fourth resistive element, a triggering energy storage means and a semiconductor device, said first resistive element serially connected with said triggering energy storage means across said energy source, said second resistive element connected from the junction of said first resistive element and said triggering energy storage means to said semiconductor device, said third resistive element connected fRom said semiconductor device to said first resistive element and said energy source, said fourth resistive element connected from said semiconductor device to said triggering energy storage means, said semiconductor device also connected to said gating electrode of said controlled rectifier, said semiconductor device conducting upon the storage of a predetermined amount of energy by said triggering energy storage means to actuate said controlled rectifier to discharge said capacitor through said electromagnetic means.
 3. The solid state bell ringing system of claim 2 wherein a fifth resistive element is connected from the junction of said third resistive element and said semiconductor device to said energy source.
 4. The solid state bell ringing system of claim 3 wherein a coupling capacitor is interposed between said semiconductor device and said gate electrode of said controlled rectifier.
 5. The solid state bell ringing system of claim 4 wherein a sixth resistive element is connected from the junction of said coupling capacitor and said gate to said power source.
 6. The solid state bell ringing system of claim 4 wherein said semiconductor device is a unijunction transistor having an emitter electrode, a first base electrode and a second base electrode, said emitter electrode of said unijunction transistor connected to the junction of said first resistive element and said triggering energy storage means through said second resistive element, said first base electrode of said unijunction transistor connected to said fourth resistive element and through said coupling capacitor to said gating electrode of said controlled rectifier, and said second base electrode of said unijunction transistor connected to said third resistive element. 